Can My Income Be Tampered With As The Wife Of A Spouse Who Pays Child Support?

Unfortuntely she can file such a suit.  This does not mean she will win the suit, and I would bet she doesn't win it (but for goodness sake get an attorney).  In any event, it will cost you in hassle and atty costs, which really sucks.  Some states allow you to then sue her if her suit fails and it cost you to defend yourself.  Further, some states also have laws allowing you to sue her for using the justice system as a tool of harrassment or vendetta.  In other words, if she sent you a letter, for example, in which it was obvious that her reason for sueing you was not because she needed it to support the kids, but rather as a revenge tactic, then you would have grounds for a suit.  My state, Missouri, has such a law.
 
As for attaching or garnishing your wages, I do not think she can, but depending on the state, she might be able to go after assets you both jointly own.  Assets which are yours alone, like a car or home that his name is not on the deed.. She cannot touch.

Technically, no.   Child support is typically based on three factors:  the custodial parents income, the noncustodial parents income, and the amount of time the child spends with each.  Your income doesn't matter.
now, where it might come into play is if the state tries to do a refund intercept, or garnish bank accounts if they are joint.    The state says that you can file for your half, but this is often a long processes.
Until you know where you stand, I would keep the assets as separate as possible.